A network may comprise a plurality of communications media and communications devices that facilitate the transfer of information between a transmitting terminal and at least one receiving terminal. Information may be transmitted via a network in messages, packets, and/or frames. Various communication protocols may be utilized to facilitate the transfer of information in a network. Some transport layer data protocols may control the amount of information that may be transmitted during a time interval. The transmission control protocol (TCP) may be considered to be an example of one such protocol. The TCP may limit the amount of information that is transmitted during a time interval based on a congestion window and slow start. At the beginning of transmission of an information flow, the congestion window may be set to an initial value. This may result in a relatively small amount of information being transmitted from a transmitting terminal to a receiving terminal. The receiving terminal may subsequently communicate an acknowledgement upon receipt of the information that was transmitted by the transmitting terminal.
Upon receipt of the acknowledgement, the transmitting terminal may increase the value associated with the congestion window to a number larger than the initial value, and transmit subsequent information based on the larger value that is associated with the congestion window. This may result in a larger amount of information being transmitted than during a comparable time interval in which the value associated with the congestion window is smaller. The size of the congestion window may increase with the increase in the value associated with the congestion window. A larger congestion window may also result in a higher information transfer rate between the transmitting terminal and the receiving terminal. The receiving terminal may communicate subsequent acknowledgements upon receipt of subsequent information. The transmitting terminal may continue to increase the size of the congestion window upon receipt of a subsequent acknowledgement.
In an instance in which the transmitting terminal does not receive a corresponding acknowledgement to previously transmitted information, the transmitting terminal may determine that the receiving terminal did not receive the previously transmitted information. The transmitting terminal may retransmit, or resend, previously transmitted information for which a corresponding acknowledgement was not received. In addition, the transmitting terminal may determine that congestion may exist in the network resulting in the previously transmitted information not being received by the receiving terminal. The previously transmitted information may be considered by the transmitting terminal to be “lost” in the network. In response to a determination of congestion in the network, or network congestion, the transmitting terminal may also reduce the size of the congestion window. The reduction in the size of the congestion window may result in a reduction in the information transfer rate between the transmitting terminal and the receiving terminal. Once reduced, the size of the congestion window may subsequently begin to increase once again. Thus, a slow start recovery may be initiated at the transmitting terminal.
In some wireless communications networks, fading conditions within the wireless communications medium, and not congestion within the network, may result in transmitted information not being received by the receiving terminal. The fading conditions may be temporary, thus it may be undesirable for a transmitting terminal to enter a slow start state as a result of a temporary loss of data due to fading conditions within the wireless communications medium. In some systems, TCP may be utilized for the transmission of multimedia information, comprising voice, video, and/or data. The real time nature of multimedia information may make it undesirable for the transmitting terminal to enter a slow start state.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.